Cylinder liner for opposed-piston engines



ug. H0 1948. H UEBERHERR 2,446,841

CYLINDER LINER FOR OPPOSED-PISTON ENGINES Filed May 5, 1945 INVENTOR.b5; Z/ee/fie/r Patented Aug. 10, 1948 CYLINDER LINER FOR OPPOSED-PISTONENGINES Hans Lieberherr, Winterthur, Switzerland, assignor to SulzerFreres, Societe Anonyme, Winterthur, Switzerland Application May 5,1945, Serial No. 592,232 In Switzerland May 8, 1944 7 Claims.

The invention relates to a cylinder liner for opposed-piston engines andconsists in that the middle part, in so far as it is not swept by thepiston rings, is provided with a heat protective ring and the parts ofthe liner situated on both sides of this middle part are subjected tointensive cooling by means of cooling passages.

An arrangement of the cylinder liner of an opposed-piston engine isknown in which the cooling of the middle part is efiectedby means ofholes bored obliquely to the axis, which lie nearest to the surface ofthe liner in the middle plane of the liner and on both sides of thisplane again retreat from the surface. A solution of this kind isinexpedient in so far as the cooling is particularly desired at thepoint where the piston rings lie in the upper dead centre. Further, theopenings for the threads. In other words, these valves may be fuelinjection valves and the starting valves are in the middle plane.Special measures must therefore be taken so that the cooling medium canflow round these valves. A very broken-up cylinder liner is thusobtained, with uncontrollable concentrations of stress. The object ofthe invention is on the one hand to obviate these stress concentrationsand on the other to obtain better cooling of the piston rings.

One embodiment of the invention is shown diagrammatically in thedrawing.

Fig. 1 is a longitudinal sectional view through a cylinder liner of atwo-stroke opposed-piston internal combustion engine;

Fig. 2 is an exterior side view of a cylinder liner similar to that ofFig. 1 but including a modification;

Fig. 3 is a sectional 'view taken on the line III-I11 of Fig 1, and

Fig. 4 is an enlarged fragmentary view of a modification.

As shown in Figs. 1, 2 and 3, the cylinder liner 1 which is mounted inthe jacket I has an enlarged middle part 2 located at a position midwaybetween the inner dead centers of the pistons 3 and 4. An annular groove5 is formed in the middle 'part and the heat protective ring 5 ismounted in the groove. The fuel valve 8 is mounted in an appropriateopening in the middle part and is inserted to extend into and throughthe protective ring, thereby serving to secure the ring in positionespecially preventing it from moving circumferentially. A starting valve9 may also be mounted in an appropriate opening in the middle part andinserted through the protective ring. Advantage may also be taken of thestarting valve to secure the protective ring in position in a mannersimilar to that of the fuel valve.- These threaded through the middlepart and also into threaded engagement with the protective ring.

As best shown in Figs. 1 and 2, the cylinder liner has annularenlargements I Z and I 3 longitudinally spaced from the middle part andexterior to that position which is swept by the rings of the pistons 3and 4, and especially when those pistons are at the ends of theirstrokes, as when they are at inner dead center. In each of the rings I2and I3, a plurality of relatively small passageways It and iii areformed for the circulation therethrough of a suitable cooling fluid suchas water,

for instance flowing from the cooling space 30 to the passageways I4 tothe space 3|, to the transi tion ducts I 6 into the space 32 and to thepassageways I5 to the cooling space 33. 'I'hese passageways l4 and I5may be formed by boring holes through the rings and especially at anangle oblique to the longitudinal axis of the liner as shown in Fig. 2,to the end that they maybe 7 brought very close to the inner bearingsurface of the cylinder and thereby effect arapid dissipation of heat.

The liner is preferably so formed that the exteriors of the annularrings I2 and I3 may be covered with a close fitting jacket I, and inorder to efiect a circulation of the cooling fluid through thepassageways I4 and I5, the enlarged middle part 2 is provided with anumber of longitudinal exterior transition ducts I8.

As shown in the modification illustrated in Fig. 2, the cooling passagesI 4 and I5 may be formed at one angle oblique to the longitudinal axisof the cylinder liner I and an additional set of cooling passages Il maybe formed, in either or both rings I2 and I3 at a different angleoblique to the longitudinal axis.

In the modified form of the invention illustrated in Fig. 4, theprotective ring 20 is flexible and ,resilient and is held in position inthe annular the following analysis, about 18% chromium, 8%

nickel, and 0.5% molybdenum; or a chromiumsteel having about 20%chromium.

Other metals, such as Nichrome, an alloy of nickel and chromium, may heused. j

The improvements oi the invention give the advantages that, in themiddle part, which isfnot swept by or contacted with the piston rings,high -tion 01 heat to eflect an intensive cooling.

I claim: 7

1. In a cylinder liner for a two-stroke opposedpiston internalcombustion engine fitted in a jacket having a middle part or said linerwhich is not swept by the rings on the pistons, the improvement whichcomprises a heat-protective ring mounted in the interior the middlepart, and means for cooling a part or the liner on each side oi!- themiddle part which is swept by the piston rings.

2. In a cylinder liner for a two-stroke opposedpiston internalcombustion engine fitted in a jacket having a, middle part of said linerwhich is not swept by the rings on the pistons, the improvement whichcomprises an annular interior groove in the middle part, an annularheat-protective ring mounted in the groove, means for secm'ing the ringin position, and passage means in the cylinder zones at each side of themiddle part and exterior oi the part swept by the piston rings oi. eachpiston tor the circulation therethrough of a cooling fluid to effect arapid cooling in those parts of the liner.

3. A cylinder liner according to claim 1 which comprises aheat-protective ring formed of a heat resisting alloy.

4. A cylinder liner according to claim 1 which tudinal axis ofv theliner.

comprises a fuel valve mounted in the liner, and

means connected to the fuel valve to secure the heat-protective ring inposition.

5. A cylinder liner according to claim 1 which 6. In a cylinder linerfora two-stroke opposedpiston internal .combustion engine having amiddle part which is not swept by the rings on the pistons, theimprovement which cmnprises a relatively thick part or the liner whichis not swept by the rings on the pistons and which is midway between theinner dead centers of the pistons, an annular groove in the middle part,a heat-protective ring formed or heat resistant metal mounted in theannular groove, means for securing the ring in position, a separateannular enlargement on the liner on each side of and longitudinallyspaced from the middle part, said enlargements being exterior or thatpart or the liner swept by the rings on the pistons when at inner deadcenter, and a plurality of passageways in each annular enlargement forthe circulation therein oi a cooling fluid. 7. A cylinder lineraccording to claim 6 which comprises passageways bored through saidenlargement at such angles that they approach very closely to the innerbearing surface or the cylinder liner which is swept by the pistonrings.

- HANS LIEBERHERR.

REFERENCES CITED The following references are of record in the tile ofthis patent;

UNITED STATES PATENTS Number Name Date 958,905 Bryen May 24, 19101,819,759 Valetta Aug. 18, 1931 1,930,186 Witkiewicz et a1. Oct. 17,1933 FOREIGN PATENTS Number Country Date 177,885 England Apr. 10, 1922409,579 England May 3, 1934 193,724

Switzerland Jan. 17, 1938

